It is difficult to insert a distributed winding coil made of a flat wire having a rectangular cross section of, for example, about 1 mm×about 10 mm into slots of a stator core. Because such a flat wire has rigidity and is hard to deform, different from a round wire. To solve this problem, various proposals have been made.
Patent Document 1 proposes to appropriately design the width of a wire and the inclination angle of a coil in order to easily insert the coil made of a wound wire, from inside to outside in a radial direction, into slots formed between teeth parts.
On the other hand, Patent Document 2 discloses a coil insertion method in which a wire to be inserted in the slots is lap-wound to form a coil, this coil is set in an inserting jig, the jig is put in the stator core, and the coil is inserted into the slots of the stator core from the inserting jig.
Patent Document 3 discloses a distributed winding coil having an insertion leading end portion bent toward an axis.